an arcuate wire guide that has a selectively openable and closable opening and is adapted to guide the fed wire when in the
closed position along the arcuate wire guide from a first side of the arcuate wire guide to a second side of the arcuate wire
guide, wherein the first and second sides of the arcuate wire guide are in opposite relationship with respect to the opening,

a pulling slider adapted to engage the fed wire on the first side of the arcuate wire guide and to pull the fed wire towards
the second side of the arcuate wire guide, and

a twisting unit adapted to engage the fed wire on both the first and second sides of the arcuate wire guide and to twist the
fed wire by a rotational movement.